Do I have to consider Deck stiffness as 0 if assuming diaphragm is flexible?

So This question is eating up all my team members. I reached out to senior engineers in my company and they are giving different answers. Posting it here to get some clarity if I may.

We have a building under design in High Seismic Zones (SDC D). Building has a low roof and high roof. Low roof is 20' below the high roof and wraps around the high roof like a L shape. With this roof plan, we have huge torsional irregularity type 1a and 1b according to ASCE 7-16. But ASCE 7-16 says that, these two type of irregularities needs to be considered only when Diaphragm is rigid or semi-rigid. We started the project in ETABS and applied the deck shear thickness of 0.035. Since ETABS doesnt have flexible diaphragm, only rigid or semirigid, we assigned semi-rigid diaphragm for both low and high roof.

Now, ASCE allows that metal bare deck can be classified as flexible diaphragm. Question is, if we do that, do we need to modify the deck stiffness f11,f22,f12 almost 0?

Doing so will require additional horizontal braces to redistribute the load to lateral system.

If we keep f11, f22, f12 as 1, can we still assume as flexible deck utilizing the stiffness of the deck?